[llvm] [Coverage] Rework Decision/Expansion/Branch (PR #78969)

[NAKAMURA Takumi via llvm-commits]

chapuni wrote:

Thanks @MaskRay . I know I have to do;
1. Rewrite the description (and possibly the subject)
2. Regenerate and test the testcase.o

By the way, do you have any comments in #78966?

https://github.com/llvm/llvm-project/pull/78969